Geometrical and electrical modulation on the transport property of silicene constrictions

Geometrical structure and the electron transport properties of monolayer and bilayer silicene near the semimetal-insulator transition point in tight-binding model

We investigate the electron properties of the monolayer and bilayer silicene which is the honeycomb lattice consist of silicon atoms, including the optical conductivity and charged impurity scattering, due to the quasipatricle Dirac-like behaviors near the K-point of silicene. The spin, valley, sublattice degrees of freedom are taken into consider in the multi-band tight-binding model. In momentum space, the scattering matrix which connects the two bare (without interaction) Green's functions in the quasiparticle momentum transport process, could be momentum-independent for the single impuirit…

随机空位对硅烯纳米带的自旋依赖热电性质的影响

Effects of random vacancies on the spin-dependent thermoelectric properties of silicene nanoribbon

本研究通过引入随机空位，提升了硅烯纳米带的热电效率，突破了经典热电定律限制，为高效热电和自旋热电器件开发提供了新思路。

From ballistic transport to tunneling in electromigrated ferromagnetic breakjunctions

We fabricate ferromagnetic nanowires with constrictions whose cross section can be reduced gradually from 100 nm to the atomic scale and eventually to the tunneling regime by means of electromigration. These devices are mechanically stable against magnetostriction and magnetostatic effects. We measure magnetoresistances ~ 0.3% for 100*30 nm^2 constrictions, increasing to a maximum of 80% for atomic-scale widths. These results are consistent with a geometrically-constrained domain wall trapped at the constriction. For the devices in the tunneling regime we observe large fluctuations in MR, betw…

Electrical switching and interferometry of massive Dirac particles in topological insulators constrictions

We investigate the electrical switching of charge and spin transport in a topological insulator nanoconstriction in a four terminal device. The switch of the edge channels is caused by the coupling between edge states which overlap in the constriction and by the tunneling effects at the contacts and therefore can be manipulated by tuning the applied voltages on the split-gate or by geometrical etching. The switching mechanism can be conveniently studied by electron interferometry involving the measurements of the current in different configurations of the side gates, while the applied bias fro…

Fermions in the presence of topological structures under geometric constrictions

In this work we study modifications of the spectrum of fermions interacting with kinklike structures in two-dimensional spacetime. We consider the Yukawa coupling between fermions and scalar fields that engender nontrivial internal structure and investigate how the fermion spectra change in terms of the parameters that control the kinklike configuration and the Yukawa coupling. We consider models that allow the internal structure of the kinklike solution to respond to the presence of a geometrical constriction, and show the fermion spectra may also appear directly affected by the constriction.…

Controlling the transport of electrons on superfluid $^{4}$He in symmetric and asymmetric FET-like structures

When floating on a two-dimensional (2D) surface of superfluid $^{4}$He, electrons arrange themselves in 2D crystalline structure known as Wigner crystal. In channels, the boundaries interfere the crystalline order and in case of very narrow channels one observes a quasi-1D Wigner crystal formed by just a few rows of electrons and, ultimately, one row, i.e., in the ``quantum wire'' regime. Recently, the ``quantum wire'' regime was accessed experimentally [D. Rees {\it et al.}, Phys. Rev. Lett. {\bf 108}, 176801 (2012)] resulting in unusual transport phenomena such as, e.g., oscillations in the …